In a major breakthrough police have charged a man over the alleged murder of two of the victims.

THE CASE

Sarah Spiers, 18, Jane Rimmer, 23, and Ciara Glennon, 27, were abducted off the streets of Claremont between January 1996 and March 1997.

All three women were believed to have been taken during the early hours of the morning after having fun nights out with friends.

The investigation into their deaths is the most expensive inquiry ever conducted by WA Police, who indicated in January this year that they remained confident that an arrest was possible.

Both Jane and Ciara’s body’s were later found, but the whereabouts of Sarah’s body remains a mystery.

The 20-year wait for answers has been an unimaginable ordeal for the women’s families.

THE VICTIMS

SARAH SPIERS

Camera IconSarah Spiers has been missing since 1996.Picture: PerthNow

Sarah Spiers, an 18-year-old legal secretary, is believed to be the alleged killer's first victim.

Sarah disappeared after a night out with friends in Claremont, during the early hours of January 27, 1996.

Her body has never been found, but it's suspected she's been murdered.

In a statement released to the media in January, Sarah's parents, Don and Carol Spiers said 20 years on they were still suffering.

“Time has not healed our loss,” they said. “Words are inadequate to describe our personal loss and heartbreak.

“It’s hard not to wonder what Sarah’s life and ours could have been, had she not been taken from us.

“She was so full of life and had a great love of family."

JANE RIMMER

Camera IconJane Rimmer.Picture: PerthNow, Supplied

Jane Rimmer, a "bubbly" 23-year-old childcare worker, was allegedly abducted during the early hours of June 9, 1996, after a night out with friends in Claremont.

Jane was last seen leaving Claremont’s Continental Hotel at 00.04am. She was seen standing outside Club Bay View after she declined a lift home with friends, with whom she had been drinking.

Her parents had expected their bubbly daughter for lunch that Sunday at their Wembley home.

Her body was found in bushland in Wellard on August 3, 1996.

CIARA GLENNON

Camera IconCiara Glennon aged about 23.Picture: PerthNow, Supplied

Ciara Glennon, a 27-year-old lawyer, was allegedly abducted after a night out in Claremont on March 14, 1997.

She disappeared after visiting the Continental Hotel (200m from Club Bay View).

After leaving the hotel, she was last seen outside a nearby computer shop on Stirling Highway at 00.15am on the Saturday morning. It is believed she was trying to get a taxi to go to her parents’ home in Mosman Park.

Ciara, who had just got back to Perth from a year overseas and in time for her sister’s wedding, was described by many as “sensible and outgoing".

Friends thought it was improbable that she would have got in a stranger’s car.

“It didn’t matter if she’d been drinking, she always kept her head screwed on,” said one friend.

Her body found was found in bushland in Eglinton on April 3, 1997.

THE POLICE INVESTIGATION, OPERATION MACRO

The murders of the three women, labelled the Claremont serial killings, is Australia's longest-running and most expensive police investigation.

It is the biggest and most complex murder case in WA's history and Police Commissioner Karl O'Callaghan says there is still "more work to be done".

The long-running investigation has involved hundreds of officers over 20 years.

The investigation, code named Macro, looked into Claremont abductions and murders and later expanded to include other serious crimes.

In 2015 the Special crime squad allocated extra resources to the historic case. In 2008 Police said more than 3000 people had been considered a person of interest in inquiries.

Police said there had been thousands and thousands of investigative actions.

MAN CHARGED OVER TWO MURDERS AND ATTACKS ON TWO OTHER WOMEN

Camera IconBradley Robert Edwards, 48, has been charged over two Claremont murders.Picture: PerthNow

On Thursday night, December 22, 2016, Bradley Roberts Edwards, 48, of Kewdale was charged over the murders of Jane Rimmer and Ciara Glennon.

He was also charged with the alleged abduction and sexual assault of a 17-year-old walking through a Claremont park in the early hours of February 12, 1995 and the indecent assault of a 18-year-old during a break-in at a Huntingdale home on February 15, 1988.

Police allege he acted alone.

No charges related to Ms Spiers have been made and the investigation is ongoing.